1. Filed of the Invention
The present invention relates to a system for mixing different kinds of grains.
2. Description of the Prior Art
For example, as disclosed in Japanese Utility Model Application Laid-Open No. 115345/79, a known grain mixing system includes a plurality of tanks respectively containing different kinds of grains, each of the tanks having a discharge port, and a plurality of valves each of which is disposed in communication with the discharge port of the associated tank and variable in opening degree for controlling a flow rate of the grain discharged from the discharge port of the associated tank. The grains are respectively discharged from the tanks through the valves which are adjusted in their respective opening degrees to a ratio identical with a desired mixture ratio, and are mixed with each other. Namely, in the conventional grain mixing system, the mixture ratio is given by the "volume" ratio. Weight of grain having a constant volume is varied depending upon the grain size, surface roughness, amount of moisture content and the like. Accordingly, even if the grains are mixed at a desired "volume" ratio with high acccuracy, the thus mixed grain mixture does not become a mixture mixed at a desired "weight" ratio. In general, since the grains are dealt with in terms of weight on the market, it is desirable that the mixture ratio of the respective grains is given by the weight ratio. However, conventionally, different kinds of grains are mixed at a volume ratio as a mixture ratio by the mixing system as described above, and the thus mixed grain mixture is distributed as if it is mixed at a "weight" ratio.